What should you FOIA? There's a new tool to help you figure that out.

Max Galka has worked most of his career in finance and insurance. With that work, he had to create models of natural disasters, and to do that, he had to get information on past natural disaster damage.

"And that's really when I discovered Freedom on Information," he said.

Years of FOIA requests taught Galka that there was no easy way to determine which organization had the information he wanted. What format was the information stored in? What language should he use to ensure his request actually got fulfilled? Over time, he realized there were ways, including requesting FOIA logs, to get a sense of the hidden landscape.

"There exists an enormous body of information sitting out there, not documented," he said. "So in theory, everyone has access to it, but practically speaking, it's hard."

On Tuesday, Galka launched FOIA Mapper, an open-source tool he built as a project with the Knight Prototype Fund to help other people discover what FOIA can do. Through the Protoype Fund and other foundation projects, Knight has already funded several FOIA projects, including FOIA Machine, said Chris Barr, director of media innovation at the Knight Foundation.

"This one was unique in the sense that what he’s attempted to do is use the FOIA process to sort of reverse engineer the systems that store government data so that folks would be able to ask for data in a more specific way that’s hard for the government to say no to," Barr said.

Basically, Galka FOIA'd FOIAs. He requested FOIA logs, pulled information out of scanned PDFs and looked into how systems are documented.

"Most of the work has then gone into organizing it all and making it searchable," he said.

FOIA Mapper works by offering a way for people to see what information exists, which agencies have it, what format they have it in and how to request it in a way that makes that request the most likely to be filled. You can also search the FOIA log to see what other people and news organizations are requesting.

When reached for comment, Melissa Segura, an investigative reporter with BuzzFeed News, was excited about the concept of FOIA Mapper. Reporters in big and small newsrooms are expected to cover more than they have in the past, she said, and government agencies also seem to be collecting more data.

"As a reporter, the combination of all these factors often feels overwhelming," she said in an email. "It's not unusual for me to have to fill out two or three FOIAs just to try and establish what records might be available before requesting the information I'm actually seeking."

FOIA Mapper offers two potential benefits, Segura said. Knowing what to look for helps streamline the request process, and it shows you other databases that you might not been aware of.

"That sounds like a win-win proposition for deeper reporting and increased transparency," she said.

It's also an opportunity for open-source collaboration.

The idea is that other people can add to FOIA Mapper as an open catalog, Barr said, essentially mapping once invisible government systems as they are discovered.

"The bet that we make on projects that are in this space is that if we can make the process easier and more efficient, potentially it helps move more organizations toward investigative reporting, which is timely and expensive," he said.

Galka, who also runs the data site Metrocosm, created FOIA Mapper with journalists in mind, he said, but "my theory is that there are a lot of people out there who really could benefit from this information but don't even realize it."

The hidden landscape FOIA Mapper is trying to chart isn't nearly complete, and Galka hopes the launch of FOIA Mapper will bring in feedback on how it's working and what else users would like to see.

"What I've gathered together is the low hanging fruit: the biggest record systems with the most documentation from the big federal government agencies," he said. "When you consider that every state, city, and town in the country are also subject to Freedom of Information laws, what I've put together hardly scratches the surface."